Mozilla Firefox totally blank on startup

[Mary Gardiner]

Hi,

Not filing this as a bug as I don't know whether it's Ubuntu's firefox
or the extensions I installed (User Agent Switcher and Session Saver)
but:

Firefox crashed recently, and when I restarted, it completely fails to
render: all I get is a blank window: no buttons and no menus. Oddly, the
right click menu *does* work. Does anyone have any ideas on solving this
one without deleting my profile (I don't like losing all my bookmarks
and the password database)? Any way I can delete the extensions?

-Mary